Numerous fossil-yielding sites, such as Olduvai, Turkana, and Laetoli, have excellent, datable stratigraphy, owing to the layers of volcanic tufts that have accumulated over millions of years. ———. Lindsay Hunter is a trained paleoanthropologist who uses her more than 15 years of experience to make sense of the distant past of our species in ways that can help us to build a better future. "Oldest hominins of Olduvai Gorge persisted across changing environments." ScienceDaily. This term is often used to refer to the Rift Valley, expanding from Malawi to Ethiopia. Evolution refers to the slow process of human adaptation over millions of years. Similarly, the earliest evidence for bipedalism occurs in specimens (associated with taxa such as Orrorin and Ardipithecus spp. For instance, an opposable big toe similar to chimpanzees (i.e., “primitive” or more ancestral), which could have aided in climbing trees effectively. is copyrighted and used for educational and noncommercial purposes as outlined by the Smithsonian. In the face of changing habitats, early humans did not substantially alter their toolkits, but instead their technology remained stable over time. Hlazo, N. 2015. During these periods, changes in solar precessional cycles increased the monsoonal system, causing more rain in East Africa, thereby increasing lake sizes. The earliest dated hominin find (between 6 mya and 7 mya, based on radiometric dating of volcanic tufts) has been argued to come from Chad and is named Sahelanthropus tchadensis (Figure 9.7; Brunet et al. Interpretation(s): High levels of species diversity during these time periods as well as environmental indications of these barriers may allow for an interpretation of allopatric-speciation (i.e., speciation due to geographic barriers) events. The origin of bipedalism in hominins has been debated in paleoanthropology, but at present there are two main ideas: Most research supports the theory of an arboreal LCA (i.e., idea 1) based on skeletal morphology of early hominin genera that demonstrate adaptations for climbing but not for knuckle-walking. Rosa Moll is an archaeology Ph.D. candidate at the University of Witwatersrand. The face below the eyes is relatively flat and does not jut out anteriorly. In 2008, nine-year-old Matthew Berger, son of paleoanthropologist Lee Berger, noted a clavicle bone in some leftover mining breccia in the Malapa Fossil Site (South Africa). We identified 40 tracks, estimated to be around 90,000 years old and indicating a party of humans traveling fast down a … Diastema: A gap. Since the discovery of the Taung Child, there have been numerous Australopithecine discoveries from the region known as “The Cradle of Humankind,” recently given UNESCO World Heritage Site status as “The Fossil Hominid Sites of South Africa.” The limestone caves found in the Cradle allow for the excellent preservation of fossils. Adaptations to bipedalism include “stacking” the majority of the weight of the body over a small area around the center of gravity (i.e., the head is above the chest, which is above the pelvis, which is over the knees, which is above the feet). www.sciencedaily.com/releases/2021/01/210107083754.htm (accessed January 27, 2021). These advances in technology go together with the developments in human evolution and cognition, dispersal of populations across the African continent and the world, and climatic changes. 1994. “Zinj,” or sometimes “Nutcracker Man” (OH5), in 1959 by Mary Leakey. Lucy, Selam (Dikika Child), Laetoli Footprints. The field of grouping organisms into those of shared ancestry. Ardi demonstrates a mosaic of ancestral and derived characteristics in the postcrania. Figure 9.7c Sahelanthropus tchadensis: TM 266-01-060-1 inferior view by eFossils is copyrighted and used for noncommercial purposes as outlined by eFossils. Australopithecus africanus was found in South Africa 4. This also allows for a more fluid interpretation of the Turnover Pulse Hypothesis, where species turnover is meant to be more rapid. 1995. In Handbook of Paleoanthropology, Second Edition, edited by T. Hardt, 2071–2105. While many introductory lectures will showcase how the foramen magnum is more anteriorly placed (indicating a head that sits centrally on the body, ideal for bipedalism), Taung Child also shows very human-like dentition. Leakey, 105–123. 2012). Currently little published postcranial material. Splitters: Researchers who prefer to split a highly variable taxon into multiple groups or species. These techniques allow us to use chemistry (such as nitrogen and oxygen isotopes in shells and sediments) or pollen grains (which show directly the kinds of flora surviving in an environment at a specific time period). 1983. 2007. ScienceDaily, 7 January 2021. Despite a reduction in canine size in this species, large overall size variation indicates high levels of sexual dimorphism in this species. Silindokuhle begun his education with a B.Sc. The earliest hominins appear to have mixed morphologies for both bipedalism and arborealism. afarensis, the geographic range of the species would be extended even further. Skeletal evidence indicates that this species was bipedal, primarily through examining the pelvis and lower limb, which demonstrate a humanlike femoral neck, a valgus knee, and bowl-shaped hip. It is a highly recommended website. Such instances have occurred multiple times in the past, and the bones of some fauna (animals, like the hippopotamus) that are sensitive to these changes give us insights into these events. Hay, R. L. and M. D. Leakey. Reed, J.G. 1999), and the femur of a fragmentary partial skeleton (argued to belong to Au. 1938b. “The Pleistocene Anthropoid Apes of South Africa.” Nature 142 (3591): 377–379. Au. Among primates, large incisors are associated with food procurement or preparation (such as biting small fruits), while small incisors indicate a diet which may contain small seeds or leaves (where the preparation is primarily in the back of the mouth). Along with a reduction in canine size is the reduction or elimination of a canine diastema: a gap between the teeth on the mandible that allows room for elongated teeth on the maxilla to “fit” in the mouth. Another famous Australopithecine find from South Africa is that of the nearly complete skeleton now known as “Little Foot” (Clarke 1998; Clarke 2013). Features that are closer to those of the assumed ancestral type are referred to as P. aethiopicus, and those that have become derived are referred to as both P. boisei and P. robustus (Strait et al. Australopithecus anamensis (after “Anam,” meaning “lake” from the Turkana region in Kenya; Leakey et al. Small molars/dentition (Homo-like characteristic). Spoor, F. 2015. A specialist species can thrive only in a narrow range of environmental conditions or has a limited diet. Walker, A. C. and R. E. Leakey. He plans to extend his knowledge from both parts of the continent to assist the better understanding of how we as humans came to being. The most divergent group, however, is humans. A small brain size (370 cc), relatively large canines, projecting cheekbones, and primitive earholes show more primitive features as compared to those of more recent Australopithecines. McHenry, H. M. 2009. She has excavated at Stone Age sites across South Africa and East Africa. Researchers have suggested that in order to conclude if it is a truly bipedal species, we need to find postcranial remains such as a pelvis or a leg bone, which would support the idea of upright walking. As the ESA advanced, stone tool makers (known as knappers) began to change the ways they detached flakes and eventually were able to shape artifacts into functional tools. Sterkfontein Member 2 Foot Bones of the Oldest South African Hominid. Large femoral head and longer neck (absorbs more stress and increases the mechanical advantage). Numerous Australopithecine species have been named, but some are still only based on a handful of fossil finds, whose designations are controversial. Obligate bipedalism: Where the primary form of locomotion for an organism is bipedal. Energy conservation: modern bipedal humans conserve more energy than extant chimpanzees, which are predominantly knuckle-walking quadrupeds when walking over land. In the robust australopithecines, the specialized nature of the teeth and masticatory system, such as flaring zygomatic arches (cheekbone) to accommodate the large temporalis (chewing) muscle, indicated a shift in diet in these taxa. The ESA spanned the largest technological time period of human innovation from over 3 million years ago to around 300,000 years ago and is associated almost entirely with hominin species prior to modern Homo sapiens. “The Evolution of Australopithecus boisei.” In Evolutionary History of the “Robust” Australopithecines, edited by F. E. Grine, 247–258. Some have placed the species itself into the genus Homo, although the cranial capacity and general cranial features are not as derived. Figure 9.7d Sahelanthropus tchadensis: TM 266-01-060-1 lateral left view by eFossils is copyrighted and used for noncommercial purposes as outlined by eFossils. 2014). Some have associated the earliest tool finds from Lomekwi, Kenya, temporally (3.3 mya) and in close geographic proximity to this species/specimen. This means that if we divide the mouth into quadrants, each should have two incisors, one canine, two premolars and three molars. The hypothesis: This hypothesis was first articulated by paleoanthropologist Richard Potts (1998). “A 3.8-Million-Year-Old Hominin Cranium from Woranso-Mille, Ethiopia.” Nature 573 (7773): 214-219. Yet there are some traits that are ambiguous. An environment from a period in the Earth’s geological past. Jara, 136–151. Like the Lomekwian, there was an aim to get sharp-edged flakes, but this was achieved through a different production method. It links the high amount of climatic variability over the last 7 million years to both behavioral and morphological changes. Some early hominins appear to, for instance, have bowl-shaped pelvises (hip bones) and angled femurs suitable for bipedalism but also have retained an opposable hallux (big toe) or curved fingers and longer arms (for arboreal locomotion). Describe early hominin genera and species, including their currently understood dates and geographic expanses and what we know about them. Orthognathic: The face below the eyes is relatively flat and does not jut out anteriorly. In one controversial study in 2010, researchers argued that cut marks on a pair of animal bones from Dikika (Ethiopia), dated to 3.4 mya, were from stone tools. 1871. “Woody Cover and Hominin Environments in the Past 6 Million Years.” Nature 476: 51e56. Evolving from a non-obligate bipedal ancestor means that the adaptations we have are evolutionary compromises. . Excavation at Ewass Oldupa uncovering fossils and Oldowan stone tools Credit: Michael Petraglia Though no hominin fossils have yet been recovered from Ewass Oldupa, hominin fossils of Homo habilis were found just 350 metres away, in deposits dating to 1.82 million years ago. Have any problems using the site? Strait, D. S., F. E. Grine, and M. A. Moniz. Thick enamel and larger canines than in later hominins. As the environmental conditions changed and a savannah/grassland environment became more widespread, the tree cover would become less dense, scattered, and sparse and bipedalism therefore would become more important. These tufts may be dated using absolute dating techniques, such as Potassium-Argon dating. Isotopes: Two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons, giving them the same chemical properties but different atomic masses. In general, splitters would consider geographic differences among populations as meaning that a species is polytypic (i.e., capable of interacting and breeding biologically but having morphological population differences). These trends are all consistent with a generalist diet, incorporating more fibrous foods. africanus and is now argued to be a young male rather than an adult female cranium (Thackeray 2000, Thackeray et al. Very thick dental enamel. The most complete of these remains is best known as “Mrs. Crude/primitive stone tools resembling Oldowan (described later) have been found in association with Au. However, the strain and shock absorption at an angled knee eventually takes its toll, with runners often experiencing joint pain. A relatively large brain (400 cc to 500 cc), small canines without an associated diastema, and more rounded cranium and smaller teeth than Au. In the new study, published in Nature Communications, researchers from the Max Planck Institute for for the Science of Human History teamed up with lead partners from the University of Calgary, Canada, and the University of Dar es Salaam, Tanzania, to excavate the site of 'Ewass Oldupa' (meaning on 'the way to the Gorge' in the local Maa language, as the site straddles the path that links the canyon's rim with its bottom). One of many evidences is of the early human found in central Java of Indonesia in the late 1800s by Eugene Dubois, and later in 1937 at Sangiran site by G.H.R. In primates, these teeth usually have one or two cusps. Clade: A group of species or taxa with a shared common ancestor. Cambridge: Cambridge University Press. the diversification of multiple early hominin species. Figure 9.2 Clades original to Explorations: An Open Invitation to Biological Anthropology by Katie Nelson is under a CC BY-NC 4.0 License. We also know that early human evolution occurred in a very complicated fashion. Maslin, M. A., C. M. Brierley, A. M. Milner, S. Shultz, M. H. Trauth, and K. E. Wilson. A small brain (300 cc to 350 cc), midfacial projection, and slight prognathism show retained primitive cranial features, but the cheek bones are less flared and robust than in later hominins. This is further evidenced in the low cusps, or ridges, on the teeth, which are ideal for chewing. Give an example of both, seen in Au. In 1991 Georgian anthropologist and paleontologist David O. Lordkipanidze discovered at Dmanisi, in the Kvemo kartli region of Georgia, hominin remains first classified as a new species, Homo georgicus, but later classified within H. erectus, sometimes called Homo erectus georgicus.Since then additional fossil remains dating roughly from this period were excavated … However, some have argued that these tools are in more direct association with hominins in the genera described in this chapter (Figure 9.23). Located in the heart of eastern Africa, the Rift System is a prime region for human origins research, boasting extraordinary records of extinct human species and environmental records spanning several million years. We have multiple species (multiple genera), diverse in the extent to which they move like us and the diets on which they subsist. Within this conversation, naturalists and early paleoanthropologists (people who study human evolution) speculated as to which human traits came first. Silindokuhle has always been curious about the world around him and how it has been shaped. Wood. ———. Researchers who prefer to split a highly variable taxon into multiple groups or species. These three species have been grouped together by a majority of scholars as a genus as they share more derived features (are more closely related to each other; or, in other words, are monophyletic) than the other australopithecines (Wood 2010; Hlazo 2015; Grine 1988; Strait et al. Rigid, robust foot, without a midtarsal break. This pattern of larger posterior dentition (even relative to the incisors and canines), thick enamel, and cranial evidence for large chewing muscles is far more pronounced in a group known as the robust australopithecines, as opposed to their earlier contemporaries or predecessors, the gracile australopithecines, and certainly larger than those seen in early Homo, which emerges during this time. 1997. Selected Answer: c. Africa Correct Answer: c. Africa Question 2 5 out of 5 points Which vertebrate is a fish, has a cartilaginous skeleton, no jaws, and a tooth-covered tongue? Some argued that the diet of the robust australopithecines was so specific that any change in environment would have accelerated their extinction. Several of these fossils are fragmentary in nature, distorted, and not well preserved because they have been recovered from quarry breccia using explosives. ramidus has been found. Furthermore, the discoverers have argued that the heavy anterior dental wear patterns, relatively large anterior dentition, and smaller hind dentition of this specimen more closely resemble that of Au. This could be because they do not easily preserve or are incomplete, making it difficult to compare and place within a specific species (e.g., the patella or knee bone). Question 1 5 out of 5 points The earliest hominin fossils were found in ____. The evidence: The evidence for this theory is similar to that for the Turnover Pulse Hypothesis: large climatic variability and higher survivability of generalists versus specialists. It is worth noting that while brain size expansion is seen primarily in our genus, Homo, earlier hominin brain sizes were highly variable between and within taxa, from 300 cc (cranial capacity, cm3), estimated in Ardipithecus, to 550 cc, estimated in Paranthropus boisei. These mixed morphologies may indicate that earlier hominins were not fully obligate bipeds and thus thrived in mosaic environments. Science 269 (5223): 521–524. The large hole (foramen) at the base of the cranium, through which the spinal cord enters the skull. This would mean that both humans and chimpanzees can be considered “derived” in terms of locomotion since chimpanzees would have independently evolved knuckle-walking. ramidus. (geology, archaeology, and environmental and geographical sciences) from the University of Cape Town before moving to Wits for a B.Sc. A collection demonstrating a pattern. Burckle, 262–288. Researchers therefore argue that the cost of maintenance must yield some evolutionary benefit. “‘Lucy’ Redux: A Review of Research on Australopithecus afarensis.” American Journal of Physical Anthropology 140 (S49): 2–48. Figure 9.21a Paranthropus boisei: OH 5 anterior view by eFossils is copyrighted and used for noncommercial purposes as outlined by eFossils. 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